As an example of such apparatus as above, there is known an obstacle detecting apparatus disclosed in Patent Document 1 identified below. This apparatus is configured to detect an obstacle present around a vehicle (movable body) and then issue an alert. An apparatus prior to the invention of Patent Document 1 was configured to determine only a distance between a vehicle and an obstacle and issue an alert only when the determined distance is shorter than a predetermined distance. Therefore, this apparatus suffered the problem that with the alert based on the distance alone, it was difficult for a driver to determine which object around the vehicle was the obstacle. Whereas, the apparatus disclosed in Patent Document 1 includes a plurality of obstacle detecting sensors mounted on the vehicle for calculating the distance to the obstacle. And, based on the result of these calculations, the apparatus estimates whether the shape of the obstacle is linear (planar shape) or circular (convex shape) and displays the estimated shape.    Patent Document 1: Japanese Patent Application “Kokai” No. 2003-194938A (see P.2-3, FIGS. 1-7).